Generator lab

An emission engine, deliberately unlike the particle labs' placement engine: a goal fans into tasks, tasks fire events, events accumulate into a field, and the field re-aims the goal. One rule — morphogenesis (branching), apoptosis (decay + pruning), homeostasis (field feedback) — with a slider for every knob. Turn them and grow a coral, a spire, or a cold strike; same genome, different phenotype. The pure grammar (soma/rule.js) runs headless — it's what will later drive SVG, film frames, and 3D structure maps. Forms are grown, not drawn.